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Old 12-08-2014, 01:19 PM   #1389 (permalink)
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If we could pull this off, it would be AWESOME!

Yes, I'm totally on board - not having to have 650V of batteries would really help my project.

I'll try to catch up a bit here, starting with your link, so maybe I can help a bit - but I'm definitely on board.

- E*clipse

Originally Posted by cts_casemod View Post
The requirement is instead of having complementary PWM outputs for each timer, one needs to have a dedicated output, rather than a complementary mode as they now have.

By default thats not possible with the PIC, but perhaps with a bit of smart coding we could use the interrupts and a look up table to disable one of the channels, so that only the positive or the negative switch can be active at a given time.

For example, assuming an h bridge:
During the positive half cycle, PWM is sent to the high Igbt of leg 1 and the low IGBT of leg 2, so that the voltage is positive (DC-LINK)

During the negative half cycle PWM is sent to the low IGBT of leg 1 and the high IGBT of leg 2, so that the voltage is negative (-DC-LINK)

Here's an example for a single phase inverter using this topology
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